This invention relates generally to signal lights, more particularly, it relates to an LED (light-emitting diode) signal light wearing an optical modulating front mantle, wherein light emanated from an LED is modulated by a plurality of continuously arrayed lens humps of a correspondent opposite lens cell so that the vertical and horizontal components of light are redistributed and cast on specified areas for full application of the LED light.
Most of the conventional lighting fixtures, such as traffic lights, signal lights, etc. are using incandescent bulbs as its light source, which, however, is found particularly defective: in power consumption and lifetime that need frequent replacements from time to time; in its reflective convergent plate that may flash back sunshine to dazzle a driver; and in light-emanating manner that wastes upwardly diverged light energy.
Compared with the incandescent bulb, a mono-color LED (light-emitting diode) lamp would consume lesser power, create littler heat, and enjoy longevity. When an LED light source is applied for traffic light, signal light, etc., it can reportedly save electric energy for 80% up and reduce maintenance charge and replacement frequency accordingly, and moreover, avoid the sunshine reflection phenomenon that may put a driver under dangerous situation.
However, in consideration of the relatively narrower emission angle, the weaker radiant power (illumination intensity), and the shorter transmission valid range of the LED light source, optical modulation becomes necessary when it is applied for longer-distance illumination. By optical modulation, the orientation of the LED""s light can be adjusted and distributed again to project and concentrate most of its energy on a specified area with least quantity of LED in conformity with examination standards of signal lights and/or illumination equipment, such as the standards of traffic light of the Institute of Transportation Engineers (ITE).
In an embodiment of a conventional U.S. Pat. No. 5,174,649 shown in FIGS. 1A and 1Bxe2x80x94xe2x80x9cLED Lamp including Reactive Lens Elementxe2x80x9dxe2x80x94a plurality of concave-convex lenses 901 is arranged on a light-incident surface 900 of a lamp shade 90 for adjusting the light emanated from a LED light source 904 to become parallel beams 905 incident upon the light-incident surface 900. Then, the parallel beams 905 leave the light-incident surface 900 behind and go forward through an external surface 902, and a plurality of arcuate protruding fillets. 903 attached vertically on the external surface 902 for being converged. In this case, some defects are found as the following though light is optically modulated:
(1) The part of light beams above vision level of the pedestrian or the driver is wasted.
(2) The arcuate protruding fillets 903 are liable to be contaminated to lower down its due functions.
In an embodiment of another conventional U.S. Pat. No. 5,343,330 shown in FIG. 2xe2x80x94Double Refraction and Total Reflection Solid Non-imaging Lensxe2x80x94a storage cell 910 containing an LED light source is concavely disposed behind a plurality of lenses 91, wherein the LED light is refracted by a refraction layer 911 or total-reflected by a reflection surface 912, then passes through an emission surface 913 in parallel or in converged beams. In this case, some defects are found and described below though optical modulation is applied:
(1) The part of light beams above vision level of the pedestrian or the driver is wasted.
(2) As every piece of LED must be plugged and soldered in each storage cell, 910, it""s rather difficult for assembling a number of LEDs and lenses in such a manner as of the printed circuit board (PCB).
In an embodiment of yet another conventional U.S. Pat. No. 5,833,355 shown in FIGS. 3A, 3Bxe2x80x94LED illuminated lamp assemblyxe2x80x94a plurality of flat mirror bands 92 laid horizontally is arranged on the bottom face of a lampshade and divided into an upper and a lower half portion 920, 923 for modulation of a correspondent row of LED light source. The upper half portion 920 further comprises a plain surface 921 and a curved surface 922 for refracting light downwards, and the lower half portion 923 further comprises an upper section 924 having a plain or curved surface and a lower section 925 having a plurality of arcuate protruding fillets, wherein the upper section 924 is provided for penetration of light while the arcuate protruding fillets of the lower section 925 for modulation of horizontal light. In this case, however, light is modulated in marching direction and the portion of light above horizontal level is eliminated, there are still some defects found as the following:
(1) The flat mirror bands are liable to form light in bands that will worsen the distribution of light.
(2) The upper half portion of the mirror bands cannot be horizontally modulated so that image aberration with respect to the lower half portion is created to affect vision effect.
For improvements, optical modulation is availed upon for the LED signal light of this invention so as to eliminate above defects. The LED signal light comprises a plurality of LEDs serving for a light source mounted on a circuit board, and light is cast through a front mantle capable of optical modulation. An external lateral surface of the front mantle is a smooth plane (light-casting surface), while an internal lateral surface (light-incident surface) is provided with a plurality of lens cells located correspondingly and oppositely to the LEDs, which, the lens cells, can perform optical modulation. A plurality of lens humps is formed on surface of the lens cell opposite against the LEDs, wherein the lens humps are arrayed continuously in vertical and horizontal direction with equal or unequal curvatures; both the architecture of the cutaway and the cross sections of the lens cell implicate an arcuate curve with an opening oriented a smooth plane. After directional modulation made by the plurality of lens humps of the lens cell, the light come from the LED light source is readjusted and redistributed to cast on some specified areas, so that an efficient application of the LED light source is made possible.
The primary object of this invention is to provide an LED signal light, in which a plurality of lens cells is disposed on a light-incident surface of a front mantle, so that the vertical component of light is modulated to cast at some specified areas and the horizontal component of light is redistributed by means of light modulation of the lens cells.
Another object of this invention is to provide an LED signal light, in which a plurality of lens humps with equal or unequal curvature is intensively arrayed on a light-incident surface of a lens cell, such that the light emanated from a light source is modulated into a plurality of lighting points for redistributing the outcast light uniformly.
A yet another object of this invention is to provide an LED signal light, in which a plurality of lens cells may be reorganized to form a front mantle in any shape or configuration desired on the basis of a unit lens cell.
A further object of this invention is to provide an LED signal light, in which the light-cast surface of a front mantle is a dust-proof smooth plane.
For more detailed information regarding advantages or features of this invention, at least an example of preferred embodiment will be elucidated below with reference to the annexed drawings.